1. Field of the Invention
The present invention relates to a probe apparatus for examining an electrical characteristic of an object such as a semiconductor device.
2. Description of the Related Art
As conventionally known, a large number of semiconductor devices are formed on a semiconductor wafer by using the precision photographic transfer technique or the like, and then the wafer is diced into the semiconductor devices. In such a manufacture process of semiconductor devices, the electrical characteristics of semi-finish semiconductor devices are examined while they are still in a semiconductor wafer by using a probe apparatus. Then, only those of the semi-finished semiconductor devices judged to be good in the examination are passed onto later steps including packaging, thereby increasing productivity.
A probe apparatus of this type includes a work table movable in the X-Y-Z-.theta. directions, on which an object is placed. A probe card having a number of probes each corresponding to each one of electrode pads of a semiconductor wafer as an object of examination, is fixedly situated above the work table. The semiconductor wafer is placed on the work table, and the work table is driven such as to bring each probe into contact with the respective electrode pad of the semiconductor wafer, thus performing an examination via each probe by using a tester.
Recently, in accordance with a further decrease in the size of semiconductor devices, the integration of circuits is greatly increased. Accordingly, the size of electrode pads is reduced, and the interval between adjacent electrode pads is narrowed. For example, each electrode pad of a semiconductor device has one side of 60 .mu.m to 100 .mu.m, and the distance between adjacent electrode pads in a row is 100 .mu.m to 200 .mu.m. Therefore, as mentioned above, it is technically very difficult to arrange a large number of, for example, several hundred probes within a limited space of a probe card, and the conventional arrangement of probes is now reaching its limit.
In consideration of this, a so-called membrane-type probe card, in which a number of electrode bumps are provided on a membrane having wiring of a predetermined pattern, is proposed as disclosed in Jap. Pat. Appln. KOKAI Publication No. 2-126159 or 2-16364.
The probe apparatus disclosed in Jap. Pat. Appln. KOKAI Publication No. 2-126159 has a membrane having a number of electrode bumps and adhered to a movable ring frame. The periphery portion of the membrane is supported by a support, and a plate spring is stretched between the support and the movable ring frame. A cushion is adhered to the rear surface of the membrane, and the difference in height between electrode pads of a wafer is absorbed by the cushion. During the examination, the membrane moves in the vertical direction integrally with the movable ring frame in spite of the spring force of the plate spring, and the electrode bumps are brought into elastic contact with the electrode pads.
The probe apparatus disclosed in Jap. Pat. Appln. KOKAI Publication No. 2-163664 has substantially the same structure as that of Publication No. 2-126159 except that a swingable plate is provided on the rear surface of the membrane. In this apparatus, the membrane and the wafer are gradually set parallel to each other and brought into elastic contact with each other as the swingable plate is rotated during the examination, when the wafer and the membrane have not been parallel with each other during the examination.